US 2006/0029775 A1 discloses a single roofing shingle made by coextruding a capstock layer with a filler material, and then cutting the same into one or more individual shingles. U.S. Pat. No. 3,897,667 discloses casting a foam onto a sheet formed into a panel of shingles in a closed mold wherein closing and opening the mold is performed in a step and repeat process.
It would be advantageous to manufacture a plurality of roofing shingles continuously joined together to form a panel, which is faster to manufacture than a step and repeat process. Further it would be advantageous to manufacture the panel of roofing shingles with a polymeric foam layer which lightens the weight thereof for ease in handling, while having substantial stiffness and beam thickness to resist beam deflection. Further, it would be advantageous for the foam thickness to provide thermal insulation.
U.S. Pat. No. 5,167,781 discloses a foamed plastic material injected into a mold cavity while at an early stage of its foaming action. Foaming is completed in the mold to control finished product density. A separate assembly operation is required to join the foamed plastic material with an outer layer to form a panel. It would be advantageous to eliminate the separate assembly operation by an apparatus capable of bonding the foamed plastic layer with the outer layer while the inner layer is foamed and molded to a desired shape.
U.S. Pat. No. 6,641,384 discloses a belt mold apparatus for continuously molding a polymeric material between a pair of continuous belts, each of which continuously rotates in a loop that circumscribes spaced apart rollers. The pair of belts continuously rotate into positions adjacent each other to form a moving mold between the belts. The polymeric material in a melt state is introduced into a front end of the moving mold. The moving mold shapes the polymeric material therein to form a continuous manufactured article. The moving mold travels from front to rear, accompanying the moving belts. While the belts move rearward and then rotate away from each other, the mold opens, which releases the continuous manufactured article, such that the article withdraws from the moving mold in a rearward direction. The mold includes a vacuum manifold that draws a vacuum on the polymeric material in the mold interior, such that air in the mold interior is evacuated and the polymeric material fills the mold interior and is shaped by a vacuum molding process. Each belt is supported against a flat support belt having apertures through which the vacuum is drawn, such that the vacuum draws the belt against the support belt. A suitable support belt and vacuum manifold are disclosed in U.S. Pat. No. 5,906,840.
Each of U.S. Pat. Nos. 6,319,456 and 6,737,008 discloses a two-layer polymeric building product of continuous length that is formed with visibly aesthetic surface features on a surface of the two-layer building product by using a moving mold formed between a pair of moving belts. The belts loop around rotating rollers and travel continuously in respective loops to continuously rotate into position beside each other and form the moving mold therebetween. The building product is continuously molded lengthwise with lateral edge portions extending continuously lengthwise. Subsequent to completion of the mold, such lateral edge portions are plastically deformed while still hot, by using a mechanical means to shape a butt edge and a nailing edge, respectively. Further, a punch press is used to mechanically punch a series of apertures laterally through the nailing edge of the building product. Insulation is disclosed as being applied by spraying a foamed polyurethane emulsion.